A technique for removing a catarcteous and/or presbyopic natural lens from the capsular bag of the eye and replacing it by a lens-forming liquid material injected directly into the capsular bag is under development. This is described in for example the patent application with application number SE 0001934-9. The liquid material is a partially polymerized material, which can undergo a curing process in the eye and thereby form a solid lens implant. The lens implant acts as a substitute for the natural lens and aims to substantially restore the features of the natural lens of the young eye. Materials and methods suitable for injection and subsequent formation of an IOL (Intra Ocular Lens) are disclosed in the patent applications PCT/EP99/07781, PCT/EP99/07780, PCT/EP99/01766 and SE 0001934-9. The defect natural lens matrix can be removed by a conventional surgical method involving an ultrasound probe, such as a phacoemulsification method involving aspiration. In order to facilitate the removal of the lens matrix and the refilling with lens forming liquid material, a capsulotomy i.e. a capsulorhexis is prepared in the anterior wall of the capsular bag. The capsulorhexis is prepared from a circular or essentially circular capsultomy in the capsular bag wall, typically with a diameter of from about 0.5 to about 2.5 mm. An injection syringe needle is inserted through an incision in the eye and through the capsulorhexis into the capsular bag so the lens-forming liquid material can be injected into the capsular bag.
It has been identified as a problem in capsular bag filling processes that during the injection and before the final lens is formed liquid material can leak through the capsulorhexis. For this purpose a plug is proposed in the Japanese patent specification JP97-308946. This plug is adapted to be attached to the injection syringe needle and inserted to the eye and positioned in the right position in the rhexis when the syringe needle is inserted. A problem with this plug is that it is clamped and/or glued in the rhexis. Since the plug is relatively large and adapted to stay in the rhexis permanent optical problems could arise. Furthermore, it needs a relatively large opening in the eye to be implanted. The plug comprises also a filling tube, which has to be cut off after filling. The tube could cause a leak. The size of the plug may also influence the free movement of the capsule that is needed for an even deformation of the capsule during accommodation. In the International Patent Application published as WO 00/49976 (University of Miami), a more simple plug construction is suggested that attempts to act as a valve during the surgical process. Also this plug suffers from the drawback that it permanently locates parts of its structure outside the capsular bag after finalizing the surgery. The curved flexible member is permanently protruding from the capsular bag through its hub like attachment point to the flexible discoid flap-valve member. Consequently, the protruding parts may risk to compromise surrounding delicate eye tissues, including the iris, while they also risk generating unwanted optical side effects. It is therefore obvious that it is need for improvements in plug parts or sealing means for a capsulorhexis that has been introduced in a capsular filling process.